The present invention relates generally to ball type trailer hitches. More particularly, the present invention relates to a quick release ball hitch system particularly adapted for gooseneck trailers.
Ball and socket trailer hitch coupling assemblies have long been known in the prior art. Typical devices comprise a rigid, ball-like coupling element comprising a sphere integrally associated with a lower diverging base. The base is usually coupled to a supporting member such as a portion of a truck bumper or the like. Usually the ball includes a shaft member which extends downwardly through the planar mounting member for retention by a suitable nut. As will be recognized by those skilled in the art, a typical trailer includes an appropriately configured tongue, including a socket which mates to the ball connector.
A representative ball hitch connector is seen in U.S. Pat. No. 4,596,406 issued June 24, 1986. The latter reference discloses a hitch connector system wherein the ball diameter can be quickly adjusted to accommodate trailer couplings of different sizes. The latter reference discloses the wealth of prior art ball and socket patents, and discusses some of the problems with conventional ball and socket couplings.
It will also be well recognized by those skilled in the art that "gooseneck" trailers have relatively recently become popular. Such trailers enable the user to tow rather heavy loads much more safely and efficiently by coupling to the tow vehicle at a point near its wheeled rear axle. Gooseneck trailers include a generally C-shaped member which projects outwardly from the trailer and terminates in an appropriate socket coupling for connection to the hitch ball. It is known to mount the ball to the bed of a typical pickup truck to apply weight to the tow vehicle substantially over its rear wheeled axle. In addition, when gooseneck trailers are so coupled to the tow vehicle, the turning radius is decreased, since the trailer pivots from a point well to the front of the traditional bumper mounted trailer coupling point.
U.S. Pat. No. 3,791,674, issued Feb. 12, 1974, discloses a king-pin type coupling assembly for gooseneck trailers The latter reference is pertinent because it discloses generally planar frame plates adapted to be coupled to the bed of a truck, and a central king-pin like post supported above a circular frame element. The coupling element is pivotally displaced between an upwardly projecting operative position for coupling to the gooseneck trailer, and a lower position wherein the king-pin fits into the underside of the truck bed. This type of "retractable" trailer hitch system for gooseneck trailers is also seen in U.S. Pat. No. 4,570,966, Issued Feb. 18, 1986. The latter reference discloses a self contained housing adapted to be installed beneath the truck bed. The housing includes a hydraulic cylinder for projecting a spring biased ball coupling system upwardly through the bed so that it may be selectively deployed when hitching is necessary, and so that it may be retracted to provide a non-interfering surface during normal use of the truck.
U.S. Pat. Nos. 1,272,486, issued July 16, 1918 and 3,893,713, issued July 8, 1975 are representative of trailer hitch devices suitable for use with the goose neck configuration, which "invert" the usual socket and ball relationship. In other words, both of these references teach the use of a ball element secured to the trailer tongue, which is selectively received and captured within suitable jaw like elements normally secured to the truck chassis or frame.
In my experience with trailer hitch assemblies of the type described above and with a wide variety of other coupling devices, certain problems particularly germane to the gooseneck application remain to be resolved. First, because of the rigidity and strength requirements necessary for a safe and secure coupling, the use of pivoted or spring biased "retractable" systems is seriously in question. Internal metal fatigue, rusting and deterioration or damage from misuse can often damage critical internal moving parts. Of course, where systems such as that described in U.S. Pat. No. 3,893,713 are contemplated, the end user is confronted with a device which is unnecessarily expensive and difficult to mount or install. Where certain prior art devices require welding to be installed, current manufacturer warrantees associated with typical pickup trucks may be voided, to the considerable detriment of the owner. Finally, many known trailer hitch devices of the gooseneck variety fail to adequately distribute the load-induced stresses, resulting in twisting, shifting, and deformation of the truck bed.
Thus a quick connect/disconnect gooseneck trailer system of the ball and socket type which properly distributes force, which includes a minimum of parts, and which can be installed without welding and thereafter used without special tools is highly desirable.